Stridor due to drug-induced hypokalaemic alkalosis

A 76-year-old on long-term Lasix and Pyrogastrone presented with stridor. This became worse with local irritation, e.g. on coughing or during indirect laryngoscopy. Indirect laryngoscopy showed a narrow glottis with an otherwise normal larynx. Blood investigation showed a low serum potassium with a raised bicarbonate level, and a serum calcium level just within the acceptable normal range. A diagnosis of laryngospasm secondary to drug-induced hypokalaemic alkalosis was made. This was treated with the withdrawal of the above drugs and supplementing potassium orally.